Conventional service providing systems that include line cards with specialized services (service cards) perform load distribution such that all specialized service cards receive similar amounts of data to process. This load distribution is usually entirely based on local logic present in the service providing system. During a phase of the control session, a hash function, whose purpose is to distribute the load somewhat equally across all service cards, is typically performed on various data connection parameters to determine to which card a client's data traffic will be anchored. Anchoring a data stream to a service card essentially assigns the data stream to be processed by that service card. However, data streams often ingress on line cards that are different from their anchor service cards. In this case, the ingress line card forwards the data to the anchoring line card along a backplane, which has a finite bandwidth. Problems arise when there is a large amount of data being forwarded between line cards and service cards, leading to congestion on the backplane.
Previous attempts to reduce the use of backplane bandwidth have ensured that data traffic is anchored on the line card that receives control traffic (or the control ingress line card) if the control ingress line card has the specialized service capability. Alternatively, data traffic is directed to the line card that incurs minimal backplane bandwidth from the control ingress line card (e.g., the nearest line card with the specialized service capability). However, the distribution (or anchoring) of traffic to a line card occurs during the control session, and often, control traffic and data traffic are distributed differently. This means that control traffic might ingress on a line card that is different from the line card that receives the data traffic. This occurs because the hashing logic used to distribute traffic over the ether-channel uses parameters such as layer-4 service port information, which are distinct for control and data traffic. For example, in DTLS/CAPWAP wireless service, the layer-4 port used for control traffic is distinct from the layer-4 port used for data traffic. Thus, during the control phase, conventional service providing systems still have no information regarding which line card will receive the incoming data traffic. Anchoring the data traffic on the service card that is closest to the line card that receives the control traffic does not necessarily reduce use of the backplane bandwidth. In addition, once a data session is anchored, it is difficult and often impossible to change the anchor without disrupting the data traffic flow.